another large series of changes, related to the refactoring.

CompoundShapes are tricky to manage with respect to persistent contact points and swapped order of btCollisionObjects,
During dispatch, finding an algorith etc. order can be swapped.
fixed several other issues, related to SimpleBroadphase (removing a proxy was not working)

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.h

@@ -41,6 +41,7 @@ protected:
 	
 	void	integrateTransforms(float timeStep);
 		
+	btVector3	m_gravity;
 	
 public:
 
@@ -65,6 +66,10 @@ public:
 		return m_debugDrawer;
 	}
 
+	virtual void	setGravity(const btVector3& gravity);
+
+	virtual void	addRigidBody(btRigidBody* body);
+
 	virtual void	updateAabbs();
 };